Duncan on the Court's Public Forum Doctrine

Here is something I wrote in my article on Locke v. Davey (footnotes omitted):

The Supreme Court has classified government property opened to private expression as fitting into one of three categories of fora: such government property will be classified as either a traditional public forum, a designated public forum, or a nonpublic forum. A traditional public forum is a place, such as a park or a public street, that has “immemorially been held in trust for the use of the public and, time out of mind, ha[s] been used for purposes of assembly, communicating thoughts between citizens, and discussing public questions.” A second category of forum is the designated... public forum. Such a public forum is created when government purposefully opens its property for public expression by part or all of the public. Finally, a nonpublic forum exists when government opens its property for certain communicative purposes, but does not intend to create a designated public forum.

In the case of a designated public forum, government may not exclude “a speaker who falls within the class to which a designated public forum is made generally available,” nor “may it discriminate against speech on the basis of its viewpoint.” In the case of a nonpublic forum, the government may restrict access “as long as the restrictions are reasonable and [are] not an effort to suppress expression merely because public officials oppose the speaker's view.” Significantly, although the government may exclude speech from even a limited public forum on the basis of subject matter, viewpoint discrimination is prohibited in both public and nonpublic fora.